1570s, from Middle French naturalisation, from naturaliser (see naturalize).

naturalize

v.

"admit (an alien) to rights of a citizen," 1550s (implied in naturalized), from natural (adj.) in its etymological sense of "by birth" + -ize; in some instances from Middle French naturaliser, from natural. Of things, from 1620s; of plants or animals, from 1796. Related: Naturalizing.

(nāch'ər-ə-līz') To establish a nonnative species in a region where it is able to reproduce successfully and live alongside native species in the wild. Naturalized species may be introduced intentionally or unintentionally. Eucalyptus trees are native to Australia but have become naturalized in many other parts of the world.

naturalization definition

The process by which a foreign citizen becomes a citizen of a new country. Millions of immigrants to the United States have become American citizens. Requirements for naturalization in the United States include residency for several years, ability to communicate in English, demonstrated knowledge of American history and government, and a dedication to American values that includes no membership in subversive organizations, such as the Communist party.